The timing steps of this circuit are indicated by a 7-segment display. The circuit was found in documentation from the 90s. The capacitor next to the 555 determines the timing steges.
This Nixie pipe circuit was found in 1965 documentation. Note the high supply voltage. Appropriate...
This circuit is from a 1976 publication, but it can be assembled with modern components. For the...
Found in Popular Electronics from the 90's, this circuit consists of an audio oscillator for Morse...